In general, the majority of the injuries that occur in the manufacturing of large complex systems such as vehicles, aircraft and the like are associated with exposure to ergonomics risk factors. Epidemiologic research shows that prolonged exposures to such risks are causal factors that contribute to the onset of work related musculoskeletal disorders. Mitigation efficacy is particularly confounded by product size, shape, and configuration constraints.
Although industry standards exist to control the exposure to ergonomics risk factors, attempts to apply them by manufacturers have generally proven ineffective. As a direct result, costs of operations are negatively impacted by reduced worker productivity and product quality, and increased incident of injuries. Furthermore, inherent variation in task sequencing and process cycle times make evaluating ergonomics risks complex in larger scale manufacturing processes. Similarly, standardizing safe work practices is difficult to achieve.
Designing large complex systems for ease of assembly and manufacturing ergonomics is difficult when the size and complexity of the system, as well as cost targets, product-performance constraints and the time intervals that exist between new product development initiatives are considered. It is important therefore, to leverage opportunities to reduce the potential for injuries in production operations from exposure to ergonomics risk factors. A typical aircraft includes 100,000 assemblies that have ergonomic impact. Each of these 100,000 assemblies may have a respective work plan that typically includes 30 operations (work instructions), and each operation typically includes 20 activities (work tasks).
Ergonomic risk management during manufacturing typically occurs by an assessor's manual observation to capture the activities, ergonomic stress values and duration, and subsequent tabulation and calculations to develop an overall ergonomic assessment rating. This process is typically done while the assessor actually observes the assembly work tasks, using a paper checklist to record the worker's activities. Observation, recording and subsequent calculations to arrive at the final assessment typically takes one work day (eight working hours) per work plan, but can take even longer. For the typical aircraft with 100,000 work plans in production, this assessment may require upward of 100,000 work days, or 800,000 working hours.
Manually-performed assessments are unique that each assessor will quantify the overall forces and duration of the entire work plan, and with no attempt being made to standardize or quantify the work tasks to arrive at the final assessment. This manual process presents issues in accuracy and repeatability of the assessment in that there is no documented statement of the work tasks involved in the final assessment, and auditing of the final assessment for accuracy requires another fully-involved manual assessment.
Because the work tasks of the work plan are not documented or standardized in the manual ergonomic assessment, any changes in the work tasks or the quantity of work tasks may invalidate the ergonomic assessment and again require another fully-involved manual assessment.
The manual ergonomic assessment process is typically reactive to the release of a work plan. That is, work plans (part assemblies) are typically only assessed after its release when an ergonomic injury has already occurred, been reported, or is suspected of causing injury. This is due to a number of factors including the enormous logistics of complex systems such as aircraft and the volume of workers involved in its manufacture. The process also typically requires an assessor who is trained, skilled and certified in the ergonomic assessment process. The number of qualified assessors is typically limited, and as such, it is typically not feasible to employ enough qualified assessors for the amount of work plans to be reviewed.
Therefore, it may be desirable to have a method and apparatus that takes into account at least some of the issues discussed above, as well as possibly other issues.